1. Field of the Invention
The present invention relates to a bottle stopper and, more particularly, to a bottle stopper for a liquid container, which is expansible in a radial direction for sealing the liquid container and shrinkable in said direction for opening.
2. Description of Related Art
Liquids such as vinegar, oil, whiskey, wine, etc. are packaged in containers such as bottles or urns made of glass or potter clay. During packaging, a liquid is injected into the container, and a stopper is inserted into the mouth of the container to seal the container. The outer diameter of the stopper is slightly larger than the inner diameter of the mouth of the container to assure sealing between the inner wall of the mouth of the container and the outer periphery of the stopper mounted in the mouth. Therefore, the stopper is able to resist high pressure inside the container and, thereby, preserves the liquid in the container.
Traditional methods for sealing the mouth of a container include use of metal caps with inner threading, corks for wines, and stoppers made of a compressible material such as rubber. Metal caps cannot provide a satisfactory sealing effect for long-term preservation and require expensive sealing machines for mass production. Corks submerged in wine are liable to break, generating cork scraps in wine. Furthermore, corks are not suitable for white alcohols and liquids other than wines.
Taiwan Patent Publication No. 467850 discloses a bottle stopper including a pressing member that is pressed axially downward to force an expansible portion of a body to expand radially outward when using the bottle stopper to seal a bottle. The expansible portion of the body causes radial expansion of a peripheral wall of a resilient member to tightly press against and seal the bottle. The resilient member is made of elastomeric material to replace corks that are liable to break when opening the bottle. However, although the peripheral wall of the resilient member can radially expand by downward movement of a shank of the pressing member and the expansible portion of the body, the bottle stopper has too many elements to cut the costs thereof. Furthermore, the extent of radial expansion of the bottle stopper is limited, which is particularly true for bottles made by blowing glass materials. Further, bottles made by blowing have small protrusions or recesses in the inner wall of the neck such that precise control of the inner diameter of the neck is impossible while leakage problems arise. Further, the body of the bottle stopper includes only four petals such that the resilient member has substantially square cross sections when the petals expand radially, failing to provide efficient sealing to the inner wall of the mouth of the bottle.
Another type of conventional bottle stopper disclosed in TW Utility Model No. 327412includes a pin, and around which a resilient member, a block, a washer, and a cap are stacked in sequence. A lever is pivotally mounted to an outer face of the cap. When the lever is bent downward, a bottom of the pin is moved upward to press against and cause radial expansion of the resilient member. Thus, the length of the resilient member is compressed to produce larger radial expansion to thereby enhance sealing reliability. However, currently available automatic bottle-sealing machines cannot proceed with pivotal movement for moving the lever but perform axial downward movement. Further, the lever on the cap prevents the cap from combining with various ornamental caps for different bottles.
An adjustable type of conventional bottle stopper disclosed in TW Utility Model No. 409703 includes a knob, a resilient member, and an adjusting rod. A threaded groove is defined in a bottom of the knob, whereas the adjusting rod includes outer threading on a top thereof. After the bottle stopper is mounted in a mouth of a bottle, the adjusting rod is moved upward when the knob is turned, causing the bottom of the adjusting rod to press against and cause radial expansion of the resilient member. Thus, the length of the resilient member is compressed to produce larger radial expansion to thereby enhance sealing reliability. However, currently available automatic bottle-sealing machines can only proceed with axial downward movement. Further, free rotation of the knob occurs easily, for the bottom of the adjusting rod does not reliably press against the inner wall of the neck of the bottle, failing to achieve the expected sealing effect. Further, the bottle stopper has no means for retaining it in an appropriate threaded locking state.
The above-mentioned conventional bottle stoppers have various disadvantages and have more elements that lead to high costs. Further improvement is, thus, required.